fetal pulm physio Flashcards
alveoli formation begins when?
28 weeks
when do most alveoli form?
majority after birth
at the end of the embryonic phase (8 weeks) what has developed?
- 1st segments appear in 5 lobes of the lungs
2. pulmonary vessels have formed themselves
when are the first breathing movements?
at end of embryonic period
how breathing movements are paradoxical @ 8 weeks: when diaphragm _______, thorax moves _____
when diaphragm contracts, diaphragm moves inward
when does the embyronic period occur?
0-8 weeks
when does the pseudoglandular phase occur?
8-17 weeks
when can the type 2 pneumocytes be discerned as cubic epithelium?
at end of 17 weeks
type 1 or 2 pneumocytes develop 1st?
type 2
when does the canalicular phase occur?
16-26 weeks
when do type 1 pneumocytes develop out of type 2 pneumocytes?
canalicular phase
when does the production of amniotic fluid begin?
pseudoglandular phase
at the end of the canalicular phase, amniotic fluid is produced mostly by?
lung epithelium
when does the saccular phase occur?
24-38 weeks
during what phase do whole clusters of sacs form on the terminal bronchioli?
saccular phase
what marks the onset of functional maturation of the lung in alveolar type 2 cells?
lamellar bodies
what ratio in amniotic fluid is a measure of fetal lung maturity?
lecithin/sphingomyelin ratio
as weeks gestation incr, sphingomyelin ________, lecithin _______
sphingomyelin decreases, lecithin increases
which surfactant specific proteins are specific for immune defense functions
SP-A, SP-D
which surfactant specific proteins are critical for surface activity
SP-B, SP-C
what can you give if lecithin/sphingomyelin ratio is low
give glucocorticoids
what is an inhibitor of surfactant synthesis?
maternal diabetes
when is the alveolar phase?
36 weeks- 2 weeks post partum
when alveoli mature, they get ______ CT septa and _______alveolar epithelium
thinner CT septa and flatter alveolar epi
first breath expiration is active or inactive?
active
what does the first breath of life establish?
functional residual capacity
what activates the transepithelial Na transport?
perinatal epinephrine surge
neonates have ______nasal resistance, _______airway resistance
lower nasal resistance, higher airway resistance
neonates have a ______efficiency breathing apparatus
low
right after birth, there is a _____in pulm arteries & alveoli ratio, which ______vascualr resistance
decrease, decreases
what is important to change breathing pattern from episodic to continuous
arousal
